Glycosylation and thermodynamic versus kinetic stability of horseradish peroxidase.
The influence of N-linked glycans on the stability of glycoproteins has been studied using horseradish peroxidase isoenzyme C (HRP), which contains eight asparagine-linked glycans. HRP was deglycosylated (d-HRP) with trifluoromethanesulfonic acid and purified to an enzymatically active homogeneous protein containing (GlcNAc)2 glycans. The thermal stability of HRP and d-HRP at pH 6.0, measured by residual activity, was indistinguishable and showed transition midpoints at 57 degrees C, whereas the unfolding in guanidinium chloride at pH 7.0, 23 degrees C was 2-3-fold faster for d-HRP than for HRP. The results are compatible with a glycan-induced decrease in the dynamic fluctuation of the polypeptide chain.
Tams
J W
JW
Department of Protein Chemistry, Institute of Molecular Biology, University of Copenhagen, Denmark.
Welinder
K G
KG
D004795:Enzyme Stability; D006031:Glycosylation; D019791:Guanidine / Q000494:pharmacology; D006361:Heating; D006735:Horseradish Peroxidase / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D017510:Protein Folding; D013816:Thermodynamics
D006735:Horseradish Peroxidase; D019791:Guanidine